Single atom Cu anchored on porous polymeric carbon nitride toward peroxymonosulfate activation for emerging pollutant degradation

Abstract

Single-atom catalysts (SACs) have been increasingly investigated in Fenton-like reactions for emerging pollutant degradation. Herein, single atom Cu anchored on porous polymeric carbon nitride (SA-Cu/PCN-α) was prepared for peroxymonosulfate (PMS) activation in tetracycline (TC) removal. The as-prepared composites were comprehensively characterized by SEM, TEM, XRD, XPS, and EDS, confirming the successful incorporation of Cu single atoms and the formation of a porous heterostructure. SA-Cu/PCN-α efficiently activated peroxymonosulfate (PMS) to degrade TC, with a pseudo-first-order rate constant k of 0.843 min⁻¹—18.7-fold higher than that of pure PCN (0.045 min⁻¹). Mechanistic studies revealed that Cu single atoms modulated the electronic structure of PCN, promoting charge separation and generating abundant reactive oxygen species (ROS, primarily ¹O₂ and O₂˙⁻). Static experiments indicated that the degradation efficiency remained above 80% in a wide range of pH values (3–11) and PMS dosages (0.5–2.0 mM) within 10 min. The catalyst retained 80% activity after five cycles, demonstrating its stability. Overall, this work designs Cu SACs with promising implications for wastewater treatment.